I got the cert 10 years ago (EPA 608, not automotive EPA 609). 60 minutes of studying two different study packets I found online. Found a local test-giver, and called them up to schedule the test.

And after that you felt competent to do your own repairs? If so I know what I am doing the next few weekends.

I watched a lot of videos made by technicians and did a lot of reading. It doesn't take too long to study enough to get the basic certification, but that is not the whole story. I have done lots of electronic prototyping and test system creation, copper plumbing, etc., so I felt comfortable with tools and electro-mechanical systems. If your entire career has been behind a keyboard, you have a lot more than an hour of studying ahead of you.

Correct me if I'm wrong but I think 80% of it boils down to "do not release refrigerant gas into the atmosphere"

You're not wrong.

The test does not cover how to do repairs or fix HVACs. I learned that elsewhere.

The test (and studying for the test) does not cover how to do repairs or fix HVACs. I learned that elsewhere.